The present invention relates generally to systems for the environmental protection of serial ATA and other electronic devices and, more particularly, to advanced techniques for providing communication and configuring the operation of such environmentally protected devices.
Serial Advanced Technology Attachment (SATA) provides an interface to attach peripheral and other electronic devices to host computers or other host devices. There is a need to install SATA devices or host devices into harsh environments that exceed the design and operating parameters of the SATA devices or host devices. SATA presents design challenges in providing environmental protection while maintaining a simple and reliable host to device interface. The present invention provides a cost effective solution for such challenges.
Peripheral and other devices operating in harsh environments, such as within the equipment bay of an aircraft, are typically enclosed within a sealed vessel that provides a temperature controlled, dry, constant pressure atmosphere for the device. The peripheral or other device may also be protected with other systems such as vibration isolators or the like. The protection system is monitored and controlled with the objective of maintaining the environment within the operational range of the peripheral or other electronic device and to disable the device if that objective cannot be met.
The present invention resolves two major issues present in environmentally protecting electronic devices: (a) providing reliable electrical connectivity between a SATA host or other host device and the SATA or other electronic device while maintaining at least one device in a temperature controlled, pressurized, dry environment and (b) assuring that the SATA device is only active when the environmental conditions within the sealed vessel are maintained within the operational range of the SATA or other electronic device.
Serial ATA is presented as an example of a modern high-speed electrical interface. The SATA standard is designed to optimize the performance/price ratio. Optimization is partly accomplished by leaving only a small margin for signal degradation within the cabling and connectors used for sending signals to and receiving signals from the SATA device. Such a small signal degradation margin requires innovation when transmitting electrical signals at 3 GHz. The SATA standard addresses this by specifying twinax cables (shielded differential lines). This type of cable or any other high-speed impedance controlled solution is difficult to feed into a seal vessel.
Hermetically sealed connectors are the classic solution used to feed electrical signals into a sealed vessel that contains electronic equipment. Such sealed connectors are expensive and offer primarily basic pin and socket electrical contacts that present a risk of Radio Frequency (RF) emission and susceptibility problems. Sealed twinax connectors are a better electrical solution but are rare and expensive. The present invention utilizes specific printed circuit materials, conductive trace and via routing techniques, and sealing methods to create a pressure and moisture barrier that is capable of conducting the electrical signals into and out of a sealed environmentally controlled vessel. These materials and techniques resolve normal Printed Circuit Board (PCB) and flexible printed circuit leakage caused by both porous barrels of plated vias and moisture permeable laminate materials. The invention is applicable to any electronic device but is especially useful for high frequency signals such as those associated with SATA devices.
The second issue addressed by the present invention is to assure that the SATA device only operates when specified environmental conditions are met. This is typically accomplished in the prior art by removing power to the SATA device or requesting the SATA host to not communicate over the SATA PHY (Physical layer) interface. Such solutions require specialty power supplies or customized host software. The present invention accomplishes the same result by incorporating a PHY block circuit between the SATA device within the sealed environmentally protected vessel and the SATA host that disrupts communication over the interface. The PHY block circuit is controlled out-of-band by an environmental controller which monitors the environmental parameters such as temperature, pressure, etc. within the sealed vessel. The environmental controller has independent control over the operational state of the SATA device since, per the SATA specification, the device is inactive if the PHY interface is not established.